Holographic display has attracted widespread interest because of its ability to show the complete information of the object and bring people an unprecedented sense of presence. The absence of ideal recording materials...Holographic display has attracted widespread interest because of its ability to show the complete information of the object and bring people an unprecedented sense of presence. The absence of ideal recording materials has hampered the realization of their commercial applications. Here we report that the response time of a bismuth and magnesium codoped lithium niobate(LN:Bi,Mg) crystal is shortened to 7.2 ms and a sensitivity as high as 646 cm/J. The crystal was used to demonstrate a real-time holographic display with a refresh rate of 60 Hz, as that of the popular high-definition television. Moreover, the first-principles calculations indicate that the electron mobility while Bi occupying Nb-site is significantly greater than that in Li-site, which directly induces the fast response of LN:Bi,Mg crystals when the concentration of Mg is above its doping threshold.展开更多
We proposed a method for calculating the computer generated hologram from multi-plane 3D objects by using nonuniform sampled angular spectrum method (NUASM). Both of the holo-gram plane and the image plane are nonun...We proposed a method for calculating the computer generated hologram from multi-plane 3D objects by using nonuniform sampled angular spectrum method (NUASM). Both of the holo-gram plane and the image plane are nonuniform sampled according to the distances and positions of the three-dimensional objects. The nonuniform fast Fourier transform (NUFFT) is used to calculate the angular spectrum propagation from the image plane to the hologram plane and the hologram can be calculated in only one step. Simulation and optical experiment results show that the hologram generated in this way can reconstruct objects on multi- planes simultaneously and separately without axial distortion.展开更多
An ideal holographic 3D display should have the characteristics of large viewing angle,full color,and low speckle noise.However,the viewing angle of the holographic 3D display is usually limited by existing strategies...An ideal holographic 3D display should have the characteristics of large viewing angle,full color,and low speckle noise.However,the viewing angle of the holographic 3D display is usually limited by existing strategies,which vastly hinders its extensive application.In this paper,a large viewing angle holographic 3D display system based on maximum diffraction modulation is proposed.The core of the proposed system comprises the spatial light modulators(SLMs)and liquid crystal grating.We also present a new feasible scheme for the realization of large viewing angle holographic 3D display.This is achieved by considering the maximum diffraction angle of SLM as the limited diffraction modulation range of each image point.By doing so,we could not only give access to the maximum hologram size of the object,but also tune the reconstructed image of secondary diffraction by using a self-engineered liquid crystal grating.More importantly,the proposed maximum diffraction modulation scheme enables the viewing angle of the proposed system to be enlarged to 73.4°.The proposed system has huge application potential in the fields such as education,culture,and entertainment.展开更多
We present holographic storage of three-dimensional(3D) images and data in a photopolymer film without any applied electric field.Its absorption and diffraction efficiency are measured,and reflective analog hologram...We present holographic storage of three-dimensional(3D) images and data in a photopolymer film without any applied electric field.Its absorption and diffraction efficiency are measured,and reflective analog hologram of real object and image of digital information are recorded in the films.The photopolymer is compared with polymer dispersed liquid crystals as holographic materials.Besides holographic diffraction efficiency of the former is little lower than that of the latter,this work demonstrates that the photopolymer is more suitable for analog hologram and big data permanent storage because of its high definition and no need of high voltage electric field.Therefore,our study proposes a potential holographic storage material to apply in large size static 3D holographic displays,including analog hologram displays,digital hologram prints,and holographic disks.展开更多
In this review we will focus on recent progress in the field of two-dimensional(2D) and three-dimensional(3D)display technologies.We present the current display materials and their applications,including organic l...In this review we will focus on recent progress in the field of two-dimensional(2D) and three-dimensional(3D)display technologies.We present the current display materials and their applications,including organic light-emitting diodes(OLEDs),flexible OLEDs quantum dot light emitting diodes(QLEDs),active-matrix organic light emitting diodes(AMOLEDs),electronic paper(E-paper),curved displays,stereoscopic 3D displays,volumetric 3D displays,light field3 D displays,and holographic 3D displays.Conventional 2D display devices,such as liquid crystal devices(LCDs) often result in ambiguity in high-dimensional data images because of lacking true depth information.This review thus provides a detailed description of 3D display technologies.展开更多
A novel see-through display with a liquid crystal lens array was proposed.A liquid crystal Fresnel lens display(LCFLD) with a holographic screen was demonstrated.The proposed display system has high efficiency,simpl...A novel see-through display with a liquid crystal lens array was proposed.A liquid crystal Fresnel lens display(LCFLD) with a holographic screen was demonstrated.The proposed display system has high efficiency,simple fabrication,and low manufacturing cost due to the absence of a polarizer and color filter.展开更多
A 360° light field 3D display system is presented, which consists of a liquid crystal display, a novel triplet lenses array, and a holographic functional screen (HFS). The mapping relationship among pixels, 3D ...A 360° light field 3D display system is presented, which consists of a liquid crystal display, a novel triplet lenses array, and a holographic functional screen (HFS). The mapping relationship among pixels, 3D objects, and view- ing positions are investigated. The aberration analysis of the single lens is carried out both in the simulation and the experiment, which shows that it cannot provide an excellent 3D image to the viewers. In order to suppress the aberrations, "the primary aberration theory" and "the damped least-squares method" are used for optical analysis and lens design. A 3D image with aberration correction can be viewed around the proposed display system.展开更多
We propose an automatic three-dimensionM (3D) pupil tracking backlight system for holographic 3D display system with large image size and full-parallax accommodation effect. The proposed tracking module is applied t...We propose an automatic three-dimensionM (3D) pupil tracking backlight system for holographic 3D display system with large image size and full-parallax accommodation effect. The proposed tracking module is applied to a holographic 3D display system with two sets of directional holographic imaging module composed of 2 × 2 large scale lens array and 22-inch high-resolution liquid crystal display 3D panel. System architecture is described and experimental results are presented.展开更多
Two different methods from graphic processing unit (GPU) and central processing unit (CPU) are proposed to suitably optimize look-up table algorithms of computer generated holography (CGH). The numerical simula-...Two different methods from graphic processing unit (GPU) and central processing unit (CPU) are proposed to suitably optimize look-up table algorithms of computer generated holography (CGH). The numerical simula- tions and experimental results show that we can reconstruct a good quality object. The computation of CGH for a three-dimensional (3D) dynamic holographic display can also be sped up by programming with our proposed method. It can optimize both file loading and the inline calculation process. The phase-only CGH with gigabyte data for reconstructing 10 MB object samplings is generated. In addition, the proposed method effectively re- duced time costs of loading and writing offline tables on a CPU. It is believed the proposed method can provide high speed and huge data CGH for 3D dynamic holographic displays in the near future.展开更多
This Letter describes an approach to encode complex-amplitude light waves with spatiotemporal double-phase holograms(DPHs) for overcoming the limit of the space-bandwidth product(SBP) delivered by existing methods. To...This Letter describes an approach to encode complex-amplitude light waves with spatiotemporal double-phase holograms(DPHs) for overcoming the limit of the space-bandwidth product(SBP) delivered by existing methods. To construct DPHs, two spatially macro-pixel encoded phase components are employed in the SBP-preserved resampling of complex holograms. Four generated sub-DPHs are displayed sequentially in time for high-quality holographic image reconstruction without reducing the image size or discarding any image terms when the DPHs are interweaved. The reconstructed holographic images contain more details and less speckle noise, with their signal-to-noise ratio and structure similarity index being improved by 14.64% and 78.79%,respectively.展开更多
In order to realize holographic display of three-dimensional (3D) objects and suppress zero-order light, conjugate image, and speckle noise, a novel method is proposed based on multiple fractional Fourier transform ...In order to realize holographic display of three-dimensional (3D) objects and suppress zero-order light, conjugate image, and speckle noise, a novel method is proposed based on multiple fractional Fourier transform (M-FrFT) for cMculating holograms of 3D objects. A series of kinoforms are generated by adding pseudorandom phase factor (PPF) to object planes in calculating each kinoform, and generating the PPF randomly again in the next kinoform calculation. The reconstructed images from kinoform sequence are superposed together in order to suppress the speckle noise of reconstructed image and improve the contrast and detail resolution of the reconstructed images. The qualities of reconstructed images from single amplitude hologram, single kinoform, and kinoform sequence calculated by M-FrFT are compared. The effects of suppressing speckle noise are analyzed by calculating the speckle index of numerical reconstructed images. The analytical results illustrate that, with the proposed method for 3D holographic display, the zero-order light, conjugate image, and speckle noise can be suppressed, and the qualities of reconstructed images can be improved significantly.展开更多
As the fiat panel displays (Liquid Crystal Displays, AMOLED, etc.) reach near perfection in their viewing qualities and display areas, it is natural to seek the next level of displays, including 3D displays. There i...As the fiat panel displays (Liquid Crystal Displays, AMOLED, etc.) reach near perfection in their viewing qualities and display areas, it is natural to seek the next level of displays, including 3D displays. There is a strong surge in 3D liquid crystal displays as a result of the successful movie Avatar. Most of these 3D displays involve the employment of special glasses that allow one view perspective for each of the eyes to achieve a depth perception. Such displays are not real 3D displays. In fact, these displays can only provide one viewing perspective for all viewers, regardless of the viewer's position. In addition, a fundamental viewing problem of focusing and accommodation exist that can lead to discomfort and fatigue for many viewers. In this paper, the authors review the current status of stereoscopic 3D displays and their problems. The authors will also discuss the possibility of using fiat panels for the display of both phase and intensity of video image information, leading to the ultimate display of 3D holographic video images. Many of the fundamental issues and limitations will be presented and discussed.展开更多
In this study, we propose a holographic augmented reality (AR) display with a wide viewing zone realized by using a special-designed reflective optical element. A conical holographic optical element (HOE) is used as s...In this study, we propose a holographic augmented reality (AR) display with a wide viewing zone realized by using a special-designed reflective optical element. A conical holographic optical element (HOE) is used as such a reflective optical element. This conical HOE was implemented to reconstruct a diverging spherical wave with a wide spread angle. It has a sharp wavelength selectivity by recording it as a volume hologram, enabling augmented reality (AR) representation of real and virtual 3D objects. The quality of the generated spherical wave and the spectral reflectivity of the fabricated conical HOE were investigated. An optical superimposition between real and virtual 3D objects was demonstrated, thereby enhancing the validity of our proposed method. A horizontal viewing zone of 140° and a vertical viewing zone of 30° were experimentally confirmed. The fabrication procedure for the conical HOE is presented, and the calculation method of the computer-generated hologram (CGH) based on Fermat’s principle is explained in detail.展开更多
Light field displays comprise three-dimensional (3D) visual information presentation devices capable of providing realistic and full parallax autostereoscopic images. In this letter, the recent advances in the light...Light field displays comprise three-dimensional (3D) visual information presentation devices capable of providing realistic and full parallax autostereoscopic images. In this letter, the recent advances in the light field displays based on integral imaging (II) and holographic techniques are presented. Several advanced approaches to demonstrate the light field displays including viewing angle enhancement techniques of the II display, a fast hologram generation method using graphics processing unit (GPU) and multiple WRPs, and a holographic microscopy to display the living cells are reported. These methods improve some important constraints of the light field displays and add new features.展开更多
A multiplexed holographic display video has been achieved by using a passive azo-dye-doped liquid crystal (LC) cell. Holograms formed in this cell can be refreshed in the order of several milliseconds. By angular mu...A multiplexed holographic display video has been achieved by using a passive azo-dye-doped liquid crystal (LC) cell. Holograms formed in this cell can be refreshed in the order of several milliseconds. By angular multiplexing technique, dynamically multiplexed holographic videos are realized. Moreover, the reconstructed RGB images are merged into a color image, which illustrates the possibility of a color holographic three-dimensional (3D) display by holographic multiplexing of the LC cell.展开更多
A time-division multiplexing method for computer-generated holograms (CGHs) is proposed to solve the problem of the limited space-bandwidth product. A three-dimensional (3-D) scene is divided into multiple layers ...A time-division multiplexing method for computer-generated holograms (CGHs) is proposed to solve the problem of the limited space-bandwidth product. A three-dimensional (3-D) scene is divided into multiple layers at different depths. The CGH corresponding to each layer is calculated by an angular-spectrum algorithm that is effective at a wide range of propagation distances. All of the CGHs are combined into several group-CGHs. These group-CGHs are sequentially uploaded onto one spatial light modulator at a high frame rate. The spacebandwidth product can be benefited by the time-division processing of the CGHs. The proposed method provides a new approach to achieve high quality 3-D display with a fast and accurate CGH computation.展开更多
We propose a method to improve the quality of the reconstructed images based on compressive sensing principles. The pseudo-inverse matrix and the total variation minimization algorithms are combined to reduce the samp...We propose a method to improve the quality of the reconstructed images based on compressive sensing principles. The pseudo-inverse matrix and the total variation minimization algorithms are combined to reduce the sampling number of the computer generated hologram. Numerical simulations are performed and the results indicate that the peak signal to noise ratio is increased and the sampling ratio is decreased at the same time for holographic display.展开更多
Active metasurfaces have recently attracted more attention since they can make the light manipulation be versatile and real-time. Metasurfaces-based holography possesses the advantages of high spatial resolution and e...Active metasurfaces have recently attracted more attention since they can make the light manipulation be versatile and real-time. Metasurfaces-based holography possesses the advantages of high spatial resolution and enormous information capacity for applications in optical displays and encryption. In this work, a tunable polarization multiplexing holographic metasurface controlled by an external magnetic field is proposed. The elaborately designed nanoantennas are arranged on the magneto-optical intermediate layer, which is placed on the metallic reflecting layer. Since the non-diagonal elements of the dielectric tensor of the magneto-optical material become non-zero values once the external magnetic field is applied,the differential absorption for the left and right circularly polarized light can be generated. Meanwhile, the amplitude and phase can be flexibly modulated by changing the sizes of the nanoantennas. Based on this, the dynamic multichannel holographic display of metasurface in the linear and circular polarization channels is realized via magnetic control, and it can provide enhanced security for optical information storage. This work paves the way for the realization of magnetically controllable phase modulation, which is promising in dynamic wavefront control and optical information encryption.展开更多
Holographic displays have the promise to be the ultimate 3D display technology,able to account for all visual cues.Recent advances in photonics and electronics gave rise to high-resolution holographic display prototyp...Holographic displays have the promise to be the ultimate 3D display technology,able to account for all visual cues.Recent advances in photonics and electronics gave rise to high-resolution holographic display prototypes,indicating that they may become widely available in the near future.One major challenge in driving those display systems is computational:computer generated holography(CGH)consists of numerically simulating diffraction,which is very computationally intensive.Our goal in this paper is to give a broad overview of the state-of-the-art in CGH.We make a classification of modern CGH algorithms,we describe different algorithmic CGH acceleration techniques,discuss the latest dedicated hardware solutions and indicate how to evaluate the perceptual quality of CGH.We summarize our findings,discuss remaining challenges and make projections on the future of CGH.展开更多
Machine learning can effectively accelerate the runtime of a computer-generated hologram.However,the angular spectrum method and single fast Fresnel transform-based machine learning acceleration algorithms are still l...Machine learning can effectively accelerate the runtime of a computer-generated hologram.However,the angular spectrum method and single fast Fresnel transform-based machine learning acceleration algorithms are still limited in the field-of-view angle of projection.In this paper,we propose an efficient method for the fast generation of large field-of-view holograms combining stochastic gradient descent(SGD),neural networks,and double-sampling Fresnel diffraction(DSFD).Compared with the traditional Gerchberg-Saxton(GS)algorithm,the DSFD-SGD algorithm has better reconstruction quality.Our neural network can be automatically trained in an unsupervised manner with a training set of target images without labels,and its combination with the DSFD can improve the optimization speed significantly.The proposed DSFD-Net method can generate 2000-resolution holograms in 0.05 s.The feasibility of the proposed method is demonstrated with simulations and experiments.展开更多
基金The National Key Research and Development Program of China(Grant No.2019YFA0705000)National Natural Science Foundation of China(No.12034010)Program for Changjiang Scholars and Innovative Research Team in University(No.IRT_13R29).
文摘Holographic display has attracted widespread interest because of its ability to show the complete information of the object and bring people an unprecedented sense of presence. The absence of ideal recording materials has hampered the realization of their commercial applications. Here we report that the response time of a bismuth and magnesium codoped lithium niobate(LN:Bi,Mg) crystal is shortened to 7.2 ms and a sensitivity as high as 646 cm/J. The crystal was used to demonstrate a real-time holographic display with a refresh rate of 60 Hz, as that of the popular high-definition television. Moreover, the first-principles calculations indicate that the electron mobility while Bi occupying Nb-site is significantly greater than that in Li-site, which directly induces the fast response of LN:Bi,Mg crystals when the concentration of Mg is above its doping threshold.
文摘We proposed a method for calculating the computer generated hologram from multi-plane 3D objects by using nonuniform sampled angular spectrum method (NUASM). Both of the holo-gram plane and the image plane are nonuniform sampled according to the distances and positions of the three-dimensional objects. The nonuniform fast Fourier transform (NUFFT) is used to calculate the angular spectrum propagation from the image plane to the hologram plane and the hologram can be calculated in only one step. Simulation and optical experiment results show that the hologram generated in this way can reconstruct objects on multi- planes simultaneously and separately without axial distortion.
基金supported by the National Natural Science Foundation of China(62020106010,62275009,U22A2079,11974258).
文摘An ideal holographic 3D display should have the characteristics of large viewing angle,full color,and low speckle noise.However,the viewing angle of the holographic 3D display is usually limited by existing strategies,which vastly hinders its extensive application.In this paper,a large viewing angle holographic 3D display system based on maximum diffraction modulation is proposed.The core of the proposed system comprises the spatial light modulators(SLMs)and liquid crystal grating.We also present a new feasible scheme for the realization of large viewing angle holographic 3D display.This is achieved by considering the maximum diffraction angle of SLM as the limited diffraction modulation range of each image point.By doing so,we could not only give access to the maximum hologram size of the object,but also tune the reconstructed image of secondary diffraction by using a self-engineered liquid crystal grating.More importantly,the proposed maximum diffraction modulation scheme enables the viewing angle of the proposed system to be enlarged to 73.4°.The proposed system has huge application potential in the fields such as education,culture,and entertainment.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474194,11004037,and 61101176)the Natural Science Foundation of Shanghai,China(Grant No.14ZR1415500)
文摘We present holographic storage of three-dimensional(3D) images and data in a photopolymer film without any applied electric field.Its absorption and diffraction efficiency are measured,and reflective analog hologram of real object and image of digital information are recorded in the films.The photopolymer is compared with polymer dispersed liquid crystals as holographic materials.Besides holographic diffraction efficiency of the former is little lower than that of the latter,this work demonstrates that the photopolymer is more suitable for analog hologram and big data permanent storage because of its high definition and no need of high voltage electric field.Therefore,our study proposes a potential holographic storage material to apply in large size static 3D holographic displays,including analog hologram displays,digital hologram prints,and holographic disks.
文摘In this review we will focus on recent progress in the field of two-dimensional(2D) and three-dimensional(3D)display technologies.We present the current display materials and their applications,including organic light-emitting diodes(OLEDs),flexible OLEDs quantum dot light emitting diodes(QLEDs),active-matrix organic light emitting diodes(AMOLEDs),electronic paper(E-paper),curved displays,stereoscopic 3D displays,volumetric 3D displays,light field3 D displays,and holographic 3D displays.Conventional 2D display devices,such as liquid crystal devices(LCDs) often result in ambiguity in high-dimensional data images because of lacking true depth information.This review thus provides a detailed description of 3D display technologies.
基金Project supported by Partner State Key Laboratory on Advanced Displays and Optoelectronics Technologies HKUST,Chinathe National Natural Science Foundation of China(Grant Nos.61435008 and 61575063)the Fundamental Research Funds for the Central Universities,China(Grant No.WM1514036)
文摘A novel see-through display with a liquid crystal lens array was proposed.A liquid crystal Fresnel lens display(LCFLD) with a holographic screen was demonstrated.The proposed display system has high efficiency,simple fabrication,and low manufacturing cost due to the absence of a polarizer and color filter.
基金supported by the BUPT Excellent Ph.D.Students Foundation(No.CX2016306)the National Natural Science Foundation of China(No.61575025)+1 种基金the National“863”Program of China(No.2015AA015902)the fund of the State Key Laboratory of Information Photonics and Optical Communications
文摘A 360° light field 3D display system is presented, which consists of a liquid crystal display, a novel triplet lenses array, and a holographic functional screen (HFS). The mapping relationship among pixels, 3D objects, and view- ing positions are investigated. The aberration analysis of the single lens is carried out both in the simulation and the experiment, which shows that it cannot provide an excellent 3D image to the viewers. In order to suppress the aberrations, "the primary aberration theory" and "the damped least-squares method" are used for optical analysis and lens design. A 3D image with aberration correction can be viewed around the proposed display system.
基金supported by Giga KOREA project(GK13D0100,Development of Telecommunications Terminal with Digital Holographic Table-top Display)
文摘We propose an automatic three-dimensionM (3D) pupil tracking backlight system for holographic 3D display system with large image size and full-parallax accommodation effect. The proposed tracking module is applied to a holographic 3D display system with two sets of directional holographic imaging module composed of 2 × 2 large scale lens array and 22-inch high-resolution liquid crystal display 3D panel. System architecture is described and experimental results are presented.
基金supported by the National High Technology Research and Development Program of China(No.2015AA015905)the National Basic Research Program of China(Nos.2013CB328801 and2013CB328806)the National Natural Science Founding of China(Nos.61420106014 and 61235002)
文摘Two different methods from graphic processing unit (GPU) and central processing unit (CPU) are proposed to suitably optimize look-up table algorithms of computer generated holography (CGH). The numerical simula- tions and experimental results show that we can reconstruct a good quality object. The computation of CGH for a three-dimensional (3D) dynamic holographic display can also be sped up by programming with our proposed method. It can optimize both file loading and the inline calculation process. The phase-only CGH with gigabyte data for reconstructing 10 MB object samplings is generated. In addition, the proposed method effectively re- duced time costs of loading and writing offline tables on a CPU. It is believed the proposed method can provide high speed and huge data CGH for 3D dynamic holographic displays in the near future.
基金supported by the National Natural Science Foundation of China (NSFC)(Nos. 61827825 and 61775117)Tsinghua University Initiative Scientific Research Program (No. 20193080075)the Cambridge Tsinghua Joint Research Initiative
文摘This Letter describes an approach to encode complex-amplitude light waves with spatiotemporal double-phase holograms(DPHs) for overcoming the limit of the space-bandwidth product(SBP) delivered by existing methods. To construct DPHs, two spatially macro-pixel encoded phase components are employed in the SBP-preserved resampling of complex holograms. Four generated sub-DPHs are displayed sequentially in time for high-quality holographic image reconstruction without reducing the image size or discarding any image terms when the DPHs are interweaved. The reconstructed holographic images contain more details and less speckle noise, with their signal-to-noise ratio and structure similarity index being improved by 14.64% and 78.79%,respectively.
基金supported by the National Natural Science Foundation of China (No. 60772124)the Shanghai University Innovation Funds for Graduates(No. Shucx080215)+1 种基金the Post-doctoral Fund by Scienceand Technology Commission of Shanghai Municipality(No. 09R21412900)the International Cooperation Project of Science and Technology Commission of Shang-hai Municipality (No. 09530708700)
文摘In order to realize holographic display of three-dimensional (3D) objects and suppress zero-order light, conjugate image, and speckle noise, a novel method is proposed based on multiple fractional Fourier transform (M-FrFT) for cMculating holograms of 3D objects. A series of kinoforms are generated by adding pseudorandom phase factor (PPF) to object planes in calculating each kinoform, and generating the PPF randomly again in the next kinoform calculation. The reconstructed images from kinoform sequence are superposed together in order to suppress the speckle noise of reconstructed image and improve the contrast and detail resolution of the reconstructed images. The qualities of reconstructed images from single amplitude hologram, single kinoform, and kinoform sequence calculated by M-FrFT are compared. The effects of suppressing speckle noise are analyzed by calculating the speckle index of numerical reconstructed images. The analytical results illustrate that, with the proposed method for 3D holographic display, the zero-order light, conjugate image, and speckle noise can be suppressed, and the qualities of reconstructed images can be improved significantly.
文摘As the fiat panel displays (Liquid Crystal Displays, AMOLED, etc.) reach near perfection in their viewing qualities and display areas, it is natural to seek the next level of displays, including 3D displays. There is a strong surge in 3D liquid crystal displays as a result of the successful movie Avatar. Most of these 3D displays involve the employment of special glasses that allow one view perspective for each of the eyes to achieve a depth perception. Such displays are not real 3D displays. In fact, these displays can only provide one viewing perspective for all viewers, regardless of the viewer's position. In addition, a fundamental viewing problem of focusing and accommodation exist that can lead to discomfort and fatigue for many viewers. In this paper, the authors review the current status of stereoscopic 3D displays and their problems. The authors will also discuss the possibility of using fiat panels for the display of both phase and intensity of video image information, leading to the ultimate display of 3D holographic video images. Many of the fundamental issues and limitations will be presented and discussed.
文摘In this study, we propose a holographic augmented reality (AR) display with a wide viewing zone realized by using a special-designed reflective optical element. A conical holographic optical element (HOE) is used as such a reflective optical element. This conical HOE was implemented to reconstruct a diverging spherical wave with a wide spread angle. It has a sharp wavelength selectivity by recording it as a volume hologram, enabling augmented reality (AR) representation of real and virtual 3D objects. The quality of the generated spherical wave and the spectral reflectivity of the fabricated conical HOE were investigated. An optical superimposition between real and virtual 3D objects was demonstrated, thereby enhancing the validity of our proposed method. A horizontal viewing zone of 140° and a vertical viewing zone of 30° were experimentally confirmed. The fabrication procedure for the conical HOE is presented, and the calculation method of the computer-generated hologram (CGH) based on Fermat’s principle is explained in detail.
基金supported by the National Research Foundation of Korea(NRF)grant,funded by the Korea government(MSIP)(No.2013-067321)partly supported by the Korea Creative Content Agency(KOCCA)in the Culture Technology(CT)Research & Development Program 2013
文摘Light field displays comprise three-dimensional (3D) visual information presentation devices capable of providing realistic and full parallax autostereoscopic images. In this letter, the recent advances in the light field displays based on integral imaging (II) and holographic techniques are presented. Several advanced approaches to demonstrate the light field displays including viewing angle enhancement techniques of the II display, a fast hologram generation method using graphics processing unit (GPU) and multiple WRPs, and a holographic microscopy to display the living cells are reported. These methods improve some important constraints of the light field displays and add new features.
基金sponsored by the National"973"Program of China(No.2013CB328804)the National Natural Science Foundation of China(No.61307028)the Science & Technology Commission of Shanghai Municipality(Nos.13ZR1420000 and 11JC1405300)
文摘A multiplexed holographic display video has been achieved by using a passive azo-dye-doped liquid crystal (LC) cell. Holograms formed in this cell can be refreshed in the order of several milliseconds. By angular multiplexing technique, dynamically multiplexed holographic videos are realized. Moreover, the reconstructed RGB images are merged into a color image, which illustrates the possibility of a color holographic three-dimensional (3D) display by holographic multiplexing of the LC cell.
基金supported by the National Basic Research Program of China (No. 2013CB328801)the National Natural Science Foundation of China (Nos. 61505095 and 61205013)
文摘A time-division multiplexing method for computer-generated holograms (CGHs) is proposed to solve the problem of the limited space-bandwidth product. A three-dimensional (3-D) scene is divided into multiple layers at different depths. The CGH corresponding to each layer is calculated by an angular-spectrum algorithm that is effective at a wide range of propagation distances. All of the CGHs are combined into several group-CGHs. These group-CGHs are sequentially uploaded onto one spatial light modulator at a high frame rate. The spacebandwidth product can be benefited by the time-division processing of the CGHs. The proposed method provides a new approach to achieve high quality 3-D display with a fast and accurate CGH computation.
基金supported by the National Basic Research Program of China(973 Program Nos.2013CB328801 and 2013CB328806)the National Natural Science Founding of China(No.61235002)
文摘We propose a method to improve the quality of the reconstructed images based on compressive sensing principles. The pseudo-inverse matrix and the total variation minimization algorithms are combined to reduce the sampling number of the computer generated hologram. Numerical simulations are performed and the results indicate that the peak signal to noise ratio is increased and the sampling ratio is decreased at the same time for holographic display.
基金supported by the National Key R&D Program of China (Nos. 2021YFB2801803 and 2021YFA1401200)the Natural Science Foundation of Shandong Province(No. ZR2023LZH001)+3 种基金the Beijing Outstanding Young Scientist Program (No. BJJWZYJH01201910007022)the National Natural Science Foundation of China (Nos. U21A20140 and 92050117)the Fok Ying-Tong Education Foundation of China(No. 161009)the Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park (No. Z211100004821009)。
文摘Active metasurfaces have recently attracted more attention since they can make the light manipulation be versatile and real-time. Metasurfaces-based holography possesses the advantages of high spatial resolution and enormous information capacity for applications in optical displays and encryption. In this work, a tunable polarization multiplexing holographic metasurface controlled by an external magnetic field is proposed. The elaborately designed nanoantennas are arranged on the magneto-optical intermediate layer, which is placed on the metallic reflecting layer. Since the non-diagonal elements of the dielectric tensor of the magneto-optical material become non-zero values once the external magnetic field is applied,the differential absorption for the left and right circularly polarized light can be generated. Meanwhile, the amplitude and phase can be flexibly modulated by changing the sizes of the nanoantennas. Based on this, the dynamic multichannel holographic display of metasurface in the linear and circular polarization channels is realized via magnetic control, and it can provide enhanced security for optical information storage. This work paves the way for the realization of magnetically controllable phase modulation, which is promising in dynamic wavefront control and optical information encryption.
基金This research was funded by the Research Foundation-Flanders(FWO),Junior postdoctoral fellowship(12ZQ220N),the joint JSPS-FWO scientific cooperation program(VS07820N)the Japan Society for the Promotion of Science(19H04132 and JPJSBP120202302)。
文摘Holographic displays have the promise to be the ultimate 3D display technology,able to account for all visual cues.Recent advances in photonics and electronics gave rise to high-resolution holographic display prototypes,indicating that they may become widely available in the near future.One major challenge in driving those display systems is computational:computer generated holography(CGH)consists of numerically simulating diffraction,which is very computationally intensive.Our goal in this paper is to give a broad overview of the state-of-the-art in CGH.We make a classification of modern CGH algorithms,we describe different algorithmic CGH acceleration techniques,discuss the latest dedicated hardware solutions and indicate how to evaluate the perceptual quality of CGH.We summarize our findings,discuss remaining challenges and make projections on the future of CGH.
基金This work was supported by the National Natural Science Foundation of China(No.61975122)the National Key Research and Development Program of China(No.2018YFA0701802).
文摘Machine learning can effectively accelerate the runtime of a computer-generated hologram.However,the angular spectrum method and single fast Fresnel transform-based machine learning acceleration algorithms are still limited in the field-of-view angle of projection.In this paper,we propose an efficient method for the fast generation of large field-of-view holograms combining stochastic gradient descent(SGD),neural networks,and double-sampling Fresnel diffraction(DSFD).Compared with the traditional Gerchberg-Saxton(GS)algorithm,the DSFD-SGD algorithm has better reconstruction quality.Our neural network can be automatically trained in an unsupervised manner with a training set of target images without labels,and its combination with the DSFD can improve the optimization speed significantly.The proposed DSFD-Net method can generate 2000-resolution holograms in 0.05 s.The feasibility of the proposed method is demonstrated with simulations and experiments.